Stone is considered a very desirable building material for its aesthetics. However, despite the desirable appeal of natural stone its use is limited by certain of its properties. In particular, natural stones are very dense, hard and have high specific gravity. Thus, stone materials are difficult to fabricate, difficult to use other than by the traditional lay up methods and require substantial structures to support the weight of the stone fabrication. Some properties for natural stone materials are summarized in Table 1 below:
TABLE 1materialspecific gravitydensity (lb/ft3)bluestone2.5–2.6159granite2.6–2.7165marble2.6–2.9170sandstone2.0–2.6143slate2.6–2.9172cement11.5–2.4100–1441The specific gravity and density of cement materials will depend on the filler materials used.
In an effort to maintain the aesthetics appeal of natural stone products while overcoming some of their problems, various polymer-based solid surface materials have been produced. One example of such solid surface material is CORIAN, available from DuPont de NEMOURS and Company. These solid surface materials are easier to fabricate than natural stone products. Unfortunately, solid surface materials are readily distinguishable from natural stone products, as the appearance of known solid surface products can be described as a speckled solid color that does not closely approximate the more complicated look and texture of natural stone. Further, most solid surface products exhibit specific gravities of 1.7 to 1.8. Thus, considerable support is still required for structures fabricated from such high density solid surface products.
High density solid surface products are also difficult to manufacture. Typically, such products require considerable mixing and careful removal of all air from the mixture after the components are mixed and prior to casting or forming the solid surface product. Naturally, this makes manufacture of the high density solid surface products themselves, as opposed to manufacture of an article from a previously fabricated high density solid surface product, difficult outside of a fairly sophisticated manufacturing facility. Thus, there remains a demand for a low density product having the appearance and texture of natural stone that can be readily prepared and used at the final location.
Engineered stone is an attempt to provide man-made materials that are more reminiscent of natural stone than solid surface materials. Engineered stone typically comprises substantial amounts of natural stone filler combined with a small amount of binder. The binder may be a polymer resin or cement. Engineered stone achieves a much more “natural” look than solid surface materials. However, engineered stone is a high density material with typical densities running over 2 grams per cubic centimeter (g/cc). Additionally, engineered stone precursors such as slabs or sheets are manufactured using sophisticated processes. Such engineered stone products are not suitable for manufacture from raw materials at an installation site. Additionally, engineered stone products retain the hardness of natural stone, making cutting, drilling and forming of the engineered stone products difficult without specialized tools and procedures.